Manny Pacquiao has tabled his most enticing offer yet to Floyd Mayweather in a bid to bring one of the most anticipated bouts in recent history to the ring.

WBC welterweight champion Mayweather and Pacquiao, who holds the WBO welterweight belt, are widely regarded as the two best pound-for-pound fighters in boxing today, but despite huge interest in a showdown all manner of stumbling blocks have prevented the duo stepping through the ropes.

Money has been a key factor in the breakdown in negotiations that have been strained ever since Mayweather and Pacquiao saw their first planned fight cancelled in March 2010. Their latest bid to stage a fight on May 5 also broke down, with Mayweather opting to face Miguel Cotto instead. Pacquiao will defend his WBO title against Timothy Bradley a month later.

Mayweather approached Pacquiao with an offer of a flat $40 million, with all pay-per-view revenue going the American's way. The Filipino's promoter, Bob Arum, responded by turning the tables on Mayweather with a counter-offer of $50m in exchange for the PPV money, before returning with a proposal to split the television money 55-45 to the winner.

Mayweather turned both offers down, insisting he will not budge on the option of receiving the entire PPV income, which has been estimated to be worth around $150m.

"I gave this sport my whole life and I've been in this sport - dominating," said Mayweather. "I have record breaking numbers that I've done. He has no record breaking numbers. With or without Pacquiao, Floyd Mayweather is okay, because when your career is over and is all said and done, I have to be happy and have to be comfortable.

"I come first, self-preservation. I put myself first. If the fight happens, it do [sic]. Do I want the fight to happen? Absolutely, but if it don't, so be it."

Pacquiao's latest offer, 70% of the PPV takings to the winner according to business advisor Rex Salud in GMA News Online, is the latest instalment in the negotiation saga, and with the Filipino behind proposals that grant the winner the greater payday critics have again asked if Mayweather is ducking the fight to preserve his reputation.

"I don't fear no man. I don't fear nothing," Mayweather told NBC when asked if he was scared of Pacquiao. "And so if you are insinuating that I'm a scared fighter then why would you want to watch a scared fighter?

"Can't no fighter beat Floyd Mayweather. And if the Pacquiao fight presents itself, and everything is in order like it should be, I'll be victorious.

"He had a chance to step up to the plate, if you had done your homework - May in the past - Pacquiao has said, 'You know what, I would take less money but I didn't want to do the drug test'. Now he's saying, 'I will do the drug test, but I want 50-50'. Like I said, it is what it is."